Alcohol assisted ALD film deposition

ABSTRACT

Methods of depositing a metal selectively onto a metal surface relative to a dielectric surface are described. Methods include reducing a metal oxide surface to a metal surface and protecting a dielectric surface to minimize deposition thereon and exposing the substrate to a metal precursor and an alcohol to deposit a film.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/082,944, filed Nov. 21, 2014, the entire disclosure of which ishereby incorporated herein by reference.

FIELD

Embodiments of the disclosure generally relate to methods of selectivelydepositing a film. More particularly, embodiments of the disclosure aredirected to methods of selectively depositing a film using alcoholselective reduction and selective protection.

BACKGROUND

As the chip feature size goes below 10 nm, integration of copperinterconnect is extremely challenging, especially in the aspects ofcopper barriers and copper seed deposition. It is known that conformalcopper seed layer in gap fill is important to the integration of copperelectroplating. However, current process copper seed layer depositedfrom PVD and CVD cannot meet the demanding requirements. Direct copperfill through PVD methods, even with high temperature processes, provesto be as difficult in certain interconnect geometries.

One difficulty of the integration process is that the copper seed layershould be a continuous film. For PVD copper seed process, films areoften non-continuous and not conformal on the sidewall of the trench orvia. Existing CVD copper films are not conformal and require a highersubstrate temperature which leads to agglomeration of copper withintrench or via.

Additionally, existing copper films have impurities resulting from thethermal degradation of the metal precursors. A typical copper film mayhave in the range of 2 to 10 atomic percent carbon and nitrogen.

Therefore, there is a need in the art for methods of depositing a metalfilm onto a metal surface selectively over a dielectric surface.

SUMMARY

One or more embodiments of the disclosure are directed to methods ofdepositing a film. The method comprises exposing a substrate to a firstreactive gas comprising one or more of copper, cobalt, nickel ortungsten and a second reactive gas comprising an alcohol.

Additional embodiments of the disclosure are directed methods ofdepositing a film comprising providing a substrate having a firstsubstrate surface including a metal oxide and a second substrate surfaceincluding a dielectric. The substrate is sequentially exposed to a firstreactive gas comprising one or more of copper, cobalt, nickel ortungsten and a second reactive gas comprising an alcohol.

Further embodiments of the disclosure are directed to methods ofdepositing a film comprising providing a substrate having a firstsubstrate surface including a metal oxide and a second substrate surfaceincluding a dielectric. The substrate is exposed to a pre-treatmentcomprising an alcohol in a first process region of a processing chamberto reduce the metal oxide to a first metal and form an alkoxy-terminateddielectric surface. The substrate is moved laterally from the firstprocess region through a gas curtain to a second process region. Thesubstrate is exposed to a first reactive gas in the second processregion. The first reactive gas comprises one or more of copper, cobalt,nickel or tungsten. The substrate is laterally moved from the secondprocess region through a gas curtain to a third process region. Thesubstrate is exposed to a second reactive gas comprising a secondalcohol in the third process region. The first alcohol and the secondalcohol are each independently selected from the group consisting ofmethanol, ethanol, 1-propanol, isopropanol, 1-butanol, isobutanol,1-pentanol, isopentanol, cyclopentanol, 1-hexanol, cyclohexanol,1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol,1-tetradecanol, 1-octadecanol, allyl alcohol (2-propen-1-ol), crotylalcohol (cis or trans), methylvinylmethanol, benzyl alcohol,α-phenylethanol, 1,2-ethanediol, 1,3-propanediol,2,2-dimethyl-1-propanol (neopentyl alcohol), 2-methyl-1-propanol,3-methyl-1-butanol, 1,2-propanediol (propylene glycol), 2-butanol,β-phenylethanol, Diphenylmethanol and combinations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIGS. 1A through 1D show a processing method in accordance with one ormore embodiment of the disclosure; and

FIG. 2 shows an embodiment of a batch processing chamber in accordancewith one or more embodiment of the disclosure.

DETAILED DESCRIPTION

Embodiments of the disclosure provide a method of depositing a filmcomprising one extra pre-treatment process prior to metal deposition.Embodiments of the disclosure use a single reagent or single processstep for two purposes; reducing metal oxide (e.g., copper oxide) tometal (e.g., copper) and protecting the surface of the dielectric. Thesingle process can be performed at one process temperature.Additionally, after the metal oxide reduction and dielectric surfaceprotection with, for example, an alkoxy group, the metal precursor hassubstantially no reaction with the dielectric surface. This prevents orminimizes metal deposition on the dielectric surface and improves theselectivity of the metal deposition.

As used in this specification and the appended claims, the term“substrate” and “wafer” are used interchangeably, both referring to asurface, or portion of a surface, upon which a process acts. It willalso be understood by those skilled in the art that reference to asubstrate can also refer to only a portion of the substrate, unless thecontext clearly indicates otherwise. Additionally, reference todepositing on a substrate can mean both a bare substrate and a substratewith one or more films or features deposited or formed thereon.

A “substrate” as used herein, refers to any substrate or materialsurface formed on a substrate upon which film processing is performedduring a fabrication process. For example, a substrate surface on whichprocessing can be performed include materials such as silicon, siliconoxide, strained silicon, silicon on insulator (SOI), carbon dopedsilicon oxides, silicon nitride, doped silicon, germanium, galliumarsenide, glass, sapphire, and any other materials such as metals, metalnitrides, metal alloys, and other conductive materials, depending on theapplication. Substrates include, without limitation, semiconductorwafers. Substrates may be exposed to a pretreatment process to polish,etch, reduce, oxidize, hydroxylate, anneal and/or bake the substratesurface. In addition to film processing directly on the surface of thesubstrate itself, in the present invention, any of the film processingsteps disclosed may also be performed on an underlayer formed on thesubstrate as disclosed in more detail below, and the term “substratesurface” is intended to include such underlayer as the contextindicates. Thus for example, where a film/layer or partial film/layerhas been deposited onto a substrate surface, the exposed surface of thenewly deposited film/layer becomes the substrate surface. What a givensubstrate surface comprises will depend on what films are to bedeposited, as well as the particular chemistry used. In one or moreembodiments, the first substrate surface will comprise a metal, and thesecond substrate surface will comprise a dielectric, or vice versa. Insome embodiments, a substrate surface may comprise certain functionality(e.g., —OH, —NH, etc.).

Likewise, the films that can be used in the methods described herein arequite varied. In some embodiments, the films may comprise, or consistessentially of a metal. Examples of metal films include, but are notlimited to, cobalt (Co), copper (Cu), nickel (Ni), tungsten (W), etc. Insome embodiments, the film comprises a dielectric. Examples include,SiO₂, SiN, HfO₂, etc.

As used in this specification and the appended claims, the terms“reactive gas”, “precursor”, “reactant”, and the like, are usedinterchangeably to mean a gas that includes a species which is reactivewith a substrate surface. For example, a first “reactive gas” may simplyadsorb onto the surface of a substrate and be available for furtherchemical reaction with a second reactive gas.

One or more embodiments of the disclosure incorporate alcohol tofunction as a reducing agent to reduce a metal oxide (e.g., copperoxide) to metal (e.g., copper) and to function as a protecting agent toprotect a dielectric surface by replacing the functional group (e.g.,hydroxyl groups) with alkoxy groups. Some embodiments of the disclosureare vapor phase processes. In one or more embodiments, the processoccurs at a single temperature.

After the metal oxide reduction and dielectric surface protection withalkoxy groups, a metal precursor (e.g., a cobalt precursor) has littleor no reaction with the dielectric surface. With little or no reaction,the metal precursor is prevented from depositing on the dielectricsurface. Therefore, one or more embodiments of the disclosure improvethe selectivity of metal deposition.

In some embodiments, the process temperature is in the range of about140° C. to about 300° C. The alcohol of some embodiments is a primary(e.g., ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol,3-methyl-1-butanol) and/or secondary alcohol (e.g., iso-propanol,2-butanol, 2-pentanol, 3-pentanol, 2-hexanol, 3-hexanol, cyclopentanol,cyclohexanol). Suitable alcohols can reduce the metal oxide to metal atvapor phase at process temperature. Suitable alcohols may modify thedielectric surface to replace hydroxyl groups with alkoxy groups. In oneor more embodiments, the Cu selective deposition on Co or Ru overdielectric is improved.

Accordingly, one or more embodiments of the disclosure are directed tomethods of depositing a film. The deposited film can be a metal film ora metal-containing film. A metal-containing film can be a metal film ora mixed metal-non-metal film, for example, a metal oxide or metalnitride film, as the context implies.

Embodiments of the disclosure provide methods of selectively depositinga metal film onto one surface over a second surface. As used in thisspecification and the appended claims, the term “selectively depositinga film on one surface over another surface”, and the like, means that afirst amount of the film is deposited on the first surface and a secondamount of film is deposited on the second surface, where the secondamount of film is less than the first amount of film or none. The term“over” used in this regard does not imply a physical orientation of onesurface on top of another surface, rather a relationship of thethermodynamic or kinetic properties of the chemical reaction with onesurface relative to the other surface. For example, selectivelydepositing a cobalt film onto a copper surface over a dielectric surfacemeans that the cobalt film deposits on the copper surface and less or nocobalt film deposits on the dielectric surface; or that the formation ofthe cobalt film on the copper surface is thermodynamically orkinetically favorable relative to the formation of a cobalt film on thedielectric surface.

With reference to FIGS. 1A-1D, a substrate 10 is provided or placed intoa processing chamber. The substrate 10 has a first surface 20 whichincludes a metal oxide 30 and a second surface 40. For example, thefirst surface and the second surface may make up a semiconductor feature(e.g., a trench) in which the first surface forms a portion of thefeature (e.g., bottom of the trench) and the second surface forms aseparate part of the feature (e.g., sidewalls of the trench). As can beseen from the representation of the first surface 20 in FIG. 1A, themetal oxide 30 can be any oxide coating on the first surface 20. Forexample, the first surface can be copper with a thin layer of copperoxide on the surface. The metal oxide 30 layer can be formed by anysuitable means, either intentionally, or as a side-result of anotherprocess. For example, the oxide layer may be formed as the result ofexposure to air during movement of the substrate or can be intentionallyformed by exposure to an oxidizing gas (e.g., oxygen or ozone) oranother process, such as CMP process.

The metal oxide can be any suitable metal oxide. In some embodiments,the metal oxide 30 includes the metal of the first surface 20 so thatupon reduction of the metal oxide, the bulk metal of the first surfaceremains. In some embodiments, the metal oxide of the first substratesurface comprises one or more of copper oxide, cobalt oxide, nickeloxide and ruthenium oxide.

The second surface 40 of some embodiments includes a dielectricmaterial. In one or more embodiments, the second surface 40 comprises adielectric material with a hydroxy-terminated surface 50.Hydroxy-terminated may also be referred to as “hydroxy-modified”, andthe like, to make a surface having hydroxyl groups.

The substrate 10 including the first surface 20, metal oxide 30 andsecond surface 40 with hydroxy-terminated surface 50 are exposed to analcohol. As shown in FIG. 1B, the alcohol reduces the metal oxide 30 tothe first surface 20 (e.g., the first metal). The reduction of the metaloxide to metal may also be referred to as reduction to a zero-valentmetal. For example, copper oxide is reduced to copper.

Exposure to the alcohol also esterifies the hydroxyl-terminated surface50 of the dielectric 40 to an alkoxy-terminated 60 second surface 40. Asused in this specification and the appended claims, the term“alkoxy-terminated” means a surface with —OR groups. The term“alkoxy-terminated” and “alkoxy-modified” are used interchangeably. Analkoxy-terminated surface can have any R group depending on the alcoholused. The alkoxy group is not limited to alkanes and can be, forexample, an alkane, alkene, alkyne, cycloalkane, cycloalkene,cycloalkyne, aryl (also called an aryloxy), or combinations thereof. Forexample, a silicon dioxide dielectric having hydroxyl terminations canbe esterified with ethanol to a silicon dioxide dielectric with ethoxyterminations.

The dielectric of the second surface 40 can be any suitable dielectric.In some embodiments, the dielectric of the second surface 40 comprises alow-k dielectric. As used in this specification and the appended claims,the term low-k dielectric refers to a dielectric material having adielectric constant less than or equal to about 5.

The alcohol can be any suitable alcohol depending on, for example, thefirst surface, the second surface, the deposition temperature and thefinal metal film being formed. The alcohol of some embodiments is one ormore of a primary alcohol and a secondary alcohol.

In some embodiments, the alcohol is a primary alcohol. Suitable primaryalcohols include, but are not limited to, methanol, ethanol, 1-propanol,isopropanol, 1-butanol, 1-pentanol, isopentanol, cyclopentanol,1-hexanol, cyclohexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol,1-undecanol, 1-dodecanol, 1-tetradecanol, 1-octadecanol, allyl alcohol(2-propen-1-ol), crotyl alcohol (cis or trans), methylvinylmethanol,benzyl alcohol, α-phenylethanol, 1,2-ethanediol, 1,3-propanediol,2,2-dimethyl-1-propanol (neopentyl alcohol), 2-methyl-1-propanol,3-methyl-1-butanol and 1,2-propanediol (propylene glycol). In one ormore embodiments, the primary alcohol is selected from the groupconsisting of methanol, ethanol, 1-propanol, isopropanol, 1-butanol,1-pentanol, isopentanol, cyclopentanol, 1-hexanol, cyclohexanol,1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol,1-tetradecanol, 1-octadecanol, allyl alcohol (2-propen-1-ol), crotylalcohol (cis or trans), methylvinylmethanol, benzyl alcohol,α-phenylethanol, 1,2-ethanediol, 1,3-propanediol,2,2-dimethyl-1-propanol (neopentyl alcohol), 2-methyl-1-propanol,3-methyl-1-butanol, 1,2-propanediol (propylene glycol) and combinationsthereof.

In some embodiments, the alcohol is a secondary alcohol. Suitablesecondary alcohol include, but are not limited to, 2-butanol,β-phenylethanol, diphenylmethanol, and 1,2-propanediol (propyleneglycol). Propylene glycol (1,2-propandiol) can act as both a primary andsecondary alcohol. In one or more embodiments, the secondary alcohol isselected from the group consisting of 2-butanol, β-phenylethanol,diphenylmethanol, 1,2-propanediol (propylene glycol) and combinationsthereof.

In some embodiments, the alcohol has the general formula

where R and R′ are each independently selected from the group consistingof hydrogen, alkanes, alkenes, alkynes, cyclic alkanes, cyclic alkenes,cyclic alkynes and aromatics having in the range of 1 to 20 carbonatoms.

In some embodiments, the alcohol is a carboxylic acid. In this case, thecompound used as the alcohol is not strictly an alcohol with the formulaR—OH, but contains a hydroxyl in the form of R—COOH. In someembodiments, the alcohol is replaced with an aldehyde having the generalformula RCOH as will be understood by those skilled in the art.

In some embodiments, the alcohol is a carboxylic acid having the generalformula

where R is selected from the group consisting of hydrogen, alkanes,alkenes, alkynes, cyclic alkanes, cyclic alkenes, cyclic alkynes andaromatics having in the range of 1 to 10 carbon atoms.

In some embodiments, the reducing agent is an aldehyde instead of analcohol, the aldehyde having the general formula

where R is selected from the group consisting of hydrogen, alkanes,alkenes, alkynes, cyclic alkanes, cyclic alkenes, cyclic alkynes andaromatics having in the range of 1 to 20 carbon atoms.

The temperature at which the pre-treatment, i.e., the alcohol,carboxylic acid or aldehyde, is exposed to the substrate surfacesdepends on, for example, the first surface, the second surface, thereducing agent being used (e.g., alcohol, carboxylic acid or aldehyde),the planned future processing, the past processing and the processingequipment being used. For example, a lower temperature process may helppreserve the thermal budget of the substrate for further processing orthe reducing agent being employed has a higher boiling point. In someembodiments, the substrate surface are exposed to the alcohol, or otherreducing agent, at a temperature in the range of about 140° C. to about300° C. In one or more embodiments, the substrate surfaces are exposedto the pre-treatment (e.g., alcohol, or other reducing agent), at atemperature in the range of about 180° to about 280° C. or in the rangeof about 190° to about 270° C. or in the range of about 200° to about260° C. or in the range of about 210° to about 250° C. In someembodiments, the process temperature during pre-treatment is less thanabout 310° C., or less than about 300° C., or less than about 290° C.,or less than about 280° C., or less than about 270° C., or less thanabout 260° C., or less than about 250° C., or less than about 240° C. Insome embodiments, during pre-treatment the exposure to the reducingagent occurs in the vapor phase.

After exposure to the pre-treatment reducing agent (e.g., alcohol,aldehyde or carboxylic acid), the metal oxide film on the first surfacehas been reduced to the first metal and the second surface (e.g.,dielectric) has been protected. This enables a metal film ormetal-containing film to be deposited onto the first metal of the firstsurface selectively over deposition onto the second surface. The metalfilm can be deposited by any suitable method (e.g., atomic layerdeposition, chemical vapor deposition).

Referring to the change from FIG. 1B. to FIG. 1C, after protecting thesecond surface 40 and preparing the first surface 20 (i.e., removing theoxide layer) the substrate surfaces can be exposed to one or moredeposition gases to deposit a second metal 70, or secondmetal-containing film, onto the first surface 20. This deposition canoccur selectively on surface 20 over the alkoxy-terminated 60 secondsurface 40, or the protected second surface 40.

Any suitable metal can be deposited as the second metal ormetal-containing film. In some embodiments, the metal film comprises oneor more of cobalt, copper, nickel, tungsten and ruthenium. For example,a cobalt film may be deposited over copper with substantially nodeposition on a protected dielectric. As used in this specification andthe appended claims, the term “substantially no deposition” used in thisregard means that deposition thickness ratio of deposited layer 70 onsurface 60 over surface 20, in a ratio in the range of 0-0.1, or 0-0.01.

In some embodiments, the first surface 20 comprises copper and thesecond metal 70 comprises cobalt. In one or more embodiments, the one ormore deposition gases used to deposit the second metal 70 is one or moreof cyclopentadienylcobalt dicarbonyl (CpCoCO), dicobalt hexacarbonyltert-butylacetylene (CCTBA).bis(2,2,6,6-tetramethyl-3,5-heptaneketoiminate)cobalt,bis(dimethylamino-2-propoxy)copper, bis(dimethylamino-2-ethoxy)copper,bis(1-ethylmethylamino-2-butoxy)copper,bis(1-ethylmethylamino-2-propoxy)copper,bis(dimethylamino-2-propoxy)nickel and/orbis(2,2,6,6-tetramethyl-3,5-heptaneketoiminate)nickel.

In one or more embodiments, the first surface 20 comprises cobalt andthe second metal 70 comprises copper. In some embodiments, the firstsurface 20 comprises nickel and the second metal 70 comprises one ormore of copper and cobalt.

Once the second metal 70 has been deposited, further processing may beperformed. For example, with reference to FIGS. 1C and 1D, hydroxylationof the alkoxy-terminated 60 second surface 40 may occur. This can bedone by any suitable method or technique that can remove the alkoxyterminations from the alkoxy-terminated dielectric surface afterdepositing the second metal film such as water vapor.

Some embodiments of the disclosure are directed to metal depositionprocesses including CVD and ALD. In some embodiments, an ALD process hassequential metal precursor and alcohol pumping onto the substrate. Thismay allow the metal film to deposit conformally. The ALD process alsomakes the metal film thickness easily controllable. The use of alcoholin this ALD process is its reduction power toward metal (e.g., copper)precursors to lead clean copper films without contamination. The alcoholvapor is volatile, and its derivative product, aldehyde, is morevolatile and leaves the metal (e.g., copper) film clean.

Some embodiments of the disclosure deposit copper films bysimultaneously or sequentially exposing a substrate to a copperprecursor and an alcohol. Suitable copper precursors include, but arenot limited to bis(dimethylamino-2-propoxy)copper,bis(dimethylamino-2-ethoxy)copper, bis(methylamino-2-propoxy)copper,bis(amino-2-ethoxy)copper, bis(dimethylamino-2-methyl-2-propoxy)copper,bis(diethylamino-2-propoxy)copper, bis(2-methoxyethoxy)copper,bis(2,2,6,6-tetramethyl-3,5-heptanedionate)copper,bis(2,2,6,6-tetramethyl-3,5-heptaneketoiminate)copper,dimethylamino-2-propoxy copper (TMVS),2,2,6,6-tetramethyl-3,5-heptanedionate copper (TMVS), andfluorine-containing precursors.

One or more embodiments of the disclosure are directed to integratedprocesses for integrated circuit (IC) beginning end of line (BEOL)interconnect. Some embodiments are used in junction with barrier filmsunderneath, but not limited to, Ru, Mn, Co, Ta layers and their oxideand nitride compounds, as well as stacks of various layers.

Some embodiments of the disclosure are also useful with Cu seed used forintegration processes with Cu electroplating. Embodiments of thedisclosure include high through-put ALD Cu film deposition processeswith deposition rate as high as in the range from 0.5 Å to 3 Å/cycle.

One or more embodiment of the disclosure is directed to methods ofdepositing a film. A substrate is exposed to one or more depositiongases including a first reactive gas comprising one or more of copper,cobalt, nickel or tungsten and a second reactive gas comprising analcohol. The film formation process can occur with the same or differentalcohol as the previous reductant used to prepare the surfaces forselective deposition. For example, a first alcohol may be exposed to thesubstrate to reduce a metal surface on the substrate to zero-valentmetal and protect a dielectric followed by exposure to the firstreactive gas and the second reactive gas in which the second reactivegas comprises a different alcohol than the first alcohol.

The film formation process can be CVD process in which the firstreactive gas and the second reactive gas are exposed to the substratesurface at the same time so that the first reactive gas and the secondreactive gas mix during formation of the film.

In some embodiments, the film formation process is an ALD process inwhich the substrate, or portion of the substrate, is sequentiallyexposed to the first reactive gas and the second reactive gas.Sequential exposure means that the substrate, or portion of thesubstrate, is exposed to only one of the first reactive gas and thesecond reactive gas at any given time. In ALD processes there issubstantially no gas phase mixing of the first reactive gas and thesecond reactive gas.

The inventors have discovered that the formation of a metal ormetal-containing film using alcohol as a reductant can be performed atlower temperatures. Typical processes not incorporating the alcoholreductant are performed at higher temperatures (e.g., up to about 650°C.). At these higher temperatures, the metal precursors employed candecompose so that excess carbon and nitrogen cannot be removed (easily)from the resulting film. For example, a metal deposition employinghydrogen as a reductant is generally performed at a temperature greatthan 200° C. (typically 250° C.). At this temperature, it is likely thatthe metal precursor will decompose. In some embodiments of thedisclosure, there is substantially no gas phase decomposition of thefirst precursor. As used in this specification and the appended claims,the term “substantially no decomposition” means that there is less than1% decomposition. In some embodiments, the substrate is maintained at atemperature in the range of about 100° C. to about 250° C., or in therange of about 100° C. to about 200° C., or less than about 250° C.,200° C., 175° C., 150° C. or 125° C.

In some embodiments, the substrate comprises a first substrate surfaceincluding a metal oxide and a second substrate surface including adielectric. In one or more embodiments, the first surface comprises Co,Ru W or an oxide thereof. In some embodiments, the second surfacecomprises SiO₂. The substrate (both the first substrate surface and thesecond substrate surface) can be exposed to an alcohol to reduce themetal oxide to a first metal and form an alkoxy-terminated dielectricsurface prior to exposure to the first reactive gas.

FIG. 2 shows an embodiment of a spatial atomic layer deposition batchprocessor, referred to as a processing chamber 110. The shape of theprocessing chamber 110 and the components described are merely exemplaryand should not be taken as limiting the scope of the disclosure. Forexample the octagonal shaped processing chamber can be circular orhexagonal, etc. A load lock 112 chamber is connected to a front (whichmay be arbitrarily designated as the front) of the processing chamber110 and provides a way of isolating the interior of the processingchamber from the atmosphere outside of the processing chamber 110. Loadlock 112 can be any suitable load lock, and can operate in the manner asany suitable load lock, as is known to those skilled in the art.

A substrate 160 passes into the processing chamber 110 into a loadingregion 120. In the loading region 120, the substrate 160 can besubjected to processing conditions or can rest. Processing conditions inthe loading region can be, for example, pre-heating of the substrate 160to process temperature, exposure to a pre-treatment (e.g., alcoholexposure) or cleaning. In some embodiments, the substrate 160 is exposedto a pre-treatment comprising a gaseous alcohol to reduce a metal oxidesurface to a metal and alkoxylate a dielectric surface.

The substrate 160 is moved laterally from the loading region through agas curtain 140 to a first process region 121. The use of ordinalnumbers to describe the process regions is merely exemplary and shouldnot be taken as limiting the scope of the disclosure. Use of the terms“first process region”, “second process region”, etc., are merelyintended as a convenient way of describing different portions of theprocessing chamber. The specific location of the process regions withinthe chamber is not limited to the embodiment shown. Lateral movement ofthe substrate 160 can occur by rotation of a susceptor 166 about an axisindicated by arrow 117. In the first process region 121, the substrate160 is exposed to the first reactive gas.

The substrate 160 is moved laterally within the processing chamber 110from the first process region 121 through a gas curtain 140 to a secondprocess region 122. The gas curtains 140 provide separation between thevarious process regions within the processing chamber 110. The gascurtains are shown as a wedge shaped component with a truncated innerend but it will be understood that the gas curtain can be any shapesuitable for maintaining isolation of the process regions. The gascurtain 140 can include any suitable combination of inert gases and/orvacuum ports that are capable of separating the atmospheres of theindividual process regions. In some embodiments, the gas curtains 140comprise, in order, a vacuum port, an inert gas port and another vacuumport. At some point during movement of the substrate from the firstprocess region 121 to the second process region 122, one portion of thesubstrate is exposed to the second process region while another portionof the substrate is exposed to the first process region 121 and a centerportion is within the gas curtain 140.

In the second process region 122, the substrate 160 is exposed to thesecond reactive gas comprising an alcohol. When the loading region 120includes an alcohol treatment, the alcohol used in the loading region120 can be the same or different from the alcohol used in the secondreactive gas. For example, the substrate may be exposed to methanol inthe loading region 120 and ethanol in the second process region 122.

The substrate 160 can be continuously laterally moved along the circularpath indicated by arrow 117 to expose the substrate to the third processregion 123, fourth process region 124, fifth process region 125, sixthprocess region 126 and the seventh process region 127 and back to theloading region. In some embodiments, the loading region 120, secondprocess region 122, fourth process region 124 and sixth process region126 each expose the substrate to the second reactive gas comprising analcohol and the first process region 121, third process region 123,fifth process region 125 and seventh process region 127 each expose thesubstrate 160 to the first reactive gas. The embodiment shown in FIG. 2has a wedge shaped gas distribution assembly 130 positioned over thefirst, third, fifth and seventh process regions for clarity to show thesubstrate 160 on the susceptor 166 between gas distribution assemblies130. However, it will be understood that any or all of the processregions can have a gas distribution assembly 130 or other gas deliverysystem.

EXAMPLES

A substrate having ruthenium and silicon dioxide was exposed toCu(DMAP)₂ at 155° C. without alcohol exposure. The Cu(DMAP)₂ was pulsedfor 500 cycles. No copper film was observed on the substrates at thistemperature.

A substrate having ruthenium and silicon dioxide surface was exposed anethanol pre-treatment followed by 500 cycles of Cu(DMAP)₂ and ethanol at155° C. A copper film was deposited onto the surface at about 1.05Å/cycle. The Cu film had low resistance about 2×10⁻⁶ ohm cm.

In some embodiments, the process occurs in a batch processing chamber.For example, in a rotating platen chamber, one or more wafers are placedon a rotating holder (“platen”). As the platen rotates, the wafers movebetween various processing areas. For example, in ALD, the processingareas would expose the wafer to precursor and reactants. In addition,plasma exposure may be useful to properly treat the film or the surfacefor enhanced film growth, or to obtain desirable film properties.

Some embodiments of the disclosure process a substrate with the firstsurface and the second surface in a single processing chamber where in afirst portion of the chamber, the substrate surfaces are exposed to thereducing agent (e.g., alcohol) to reduce the metal oxide and protect thesecond surface. The substrate is rotated to a second portion, or secondand subsequent third portion or more, of the processing chamber todeposit the metal film on the first metal surface. In some embodiments,the substrate can be further rotated or moved to another portion of theprocessing chamber where the alkoxy-terminations of the second surfacecan be removed. To separate each or any of the portions, or regions, ofthe processing chamber, a gas curtain can be employed. The gas curtainprovides one or more of purge gas and vacuum ports between theprocessing regions to prevent reactive gases from moving from one regionto an adjacent region. In some embodiments, the substrate is exposed tomore than one processing region at the same time, with one portion ofthe substrate in a first region (e.g., for alcohol exposure) and anotherportion of the substrate at the same time being in a separate region(e.g., metal deposition) of the processing chamber.

Embodiments of the disclosure can be used with either a linearprocessing system or a rotational processing system. In a linearprocessing system, the width of the area that the plasma exits thehousing is substantially the same across the entire length of frontface. In a rotational processing system, the housing may be generally“pie-shaped” or “wedge-shaped”. In a wedge-shaped segment, the width ofthe area that the plasma exits the housing changes to conform to a pieshape. As used in this specification and the appended claims, the terms“pie-shaped” and “wedge-shaped” are used interchangeably to describe abody that is a generally circular sector. For example, a wedge-shapedsegment may be a fraction of a circle or disc-shaped piece. The inneredge of the pie-shaped segment can come to a point or can be truncatedto a flat edge or rounded. The path of the substrates can beperpendicular to the gas ports. In some embodiments, each of the gasinjector assemblies comprise a plurality of elongate gas ports whichextend in a direction substantially perpendicular to the path traversedby a substrate. As used in this specification and the appended claims,the term “substantially perpendicular” means that the general directionof movement of the substrates is along a plane approximatelyperpendicular (e.g., about 45° to 90°) to the axis of the gas ports. Fora wedge-shaped gas port, the axis of the gas port can be considered tobe a line defined as the mid-point of the width of the port extendingalong the length of the port.

Additional embodiments of the disclosure are directed to methods ofprocessing a plurality of substrates. The plurality of substrates isloaded onto substrate support in a processing chamber. The substratesupport is rotated to pass each of the plurality of substrates across agas distribution assembly to expose the substrate surface to thereducing agent (e.g., alcohol), deposit a film on the substrate and,optionally, remove the protection layer from the reducing agentexposure. Any of the process steps, reducing agent exposure, metaldeposition or hydroxylation can be repeated before moving to the nextprocess, or sequentially.

Rotation of the carousel can be continuous or discontinuous. Incontinuous processing, the wafers are constantly rotating so that theyare exposed to each of the injectors in turn. In discontinuousprocessing, the wafers can be moved to the injector region and stopped,and then to the region between the injectors and stopped. For example,the carousel can rotate so that the wafers move from an inter-injectorregion across the injector (or stop adjacent the injector) and on to thenext inter-injector region where the carousel can pause again. Pausingbetween the injectors may provide time for additional processing betweeneach layer deposition (e.g., exposure to plasma). The frequency of theplasma may be tuned depending on the specific reactive species beingused. Suitable frequencies include, but are not limited to, 400 kHz, 2MHz, 13.56 MHz, 27 MHz, 40 MHz, 60 MHz and 100 MHz.

According to one or more embodiments, the substrate is subjected toprocessing prior to and/or after forming the layer. This processing canbe performed in the same chamber or in one or more separate processingchambers. In some embodiments, the substrate is moved from the firstchamber to a separate, second chamber for further processing. Thesubstrate can be moved directly from the first chamber to the separateprocessing chamber, or the substrate can be moved from the first chamberto one or more transfer chambers, and then moved to the separateprocessing chamber. Accordingly, the processing apparatus may comprisemultiple chambers in communication with a transfer station. An apparatusof this sort may be referred to as a “cluster tool” or “clusteredsystem”, and the like.

Generally, a cluster tool is a modular system comprising multiplechambers which perform various functions including substratecenter-finding and orientation, degassing, annealing, deposition and/oretching. According to one or more embodiments, a cluster tool includesat least a first chamber and a central transfer chamber. The centraltransfer chamber may house a robot that can shuttle substrates betweenand among processing chambers and load lock chambers. The transferchamber is typically maintained at a vacuum condition and provides anintermediate stage for shuttling substrates from one chamber to anotherand/or to a load lock chamber positioned at a front end of the clustertool. Two well-known cluster tools which may be adapted for the presentdisclosure are the Centura® and the Endura®, both available from AppliedMaterials, Inc., of Santa Clara, Calif. The details of one suchstaged-vacuum substrate processing apparatus are disclosed in U.S. Pat.No. 5,186,718, entitled “Staged-Vacuum Wafer Processing Apparatus andMethod,” Tepman et al., issued on Feb. 16, 1993. However, the exactarrangement and combination of chambers may be altered for purposes ofperforming specific steps of a process as described herein. Otherprocessing chambers which may be used include, but are not limited to,cyclical layer deposition (CLD), atomic layer deposition (ALD), chemicalvapor deposition (CVD), physical vapor deposition (PVD), etch,pre-clean, chemical clean, thermal treatment such as RTP, plasmanitridation, degas, orientation, hydroxylation and other substrateprocesses. By carrying out processes in a chamber on a cluster tool,surface contamination of the substrate with atmospheric impurities canbe avoided without oxidation prior to depositing a subsequent film.

According to one or more embodiments, the substrate is continuouslyunder vacuum or “load lock” conditions, and is not exposed to ambientair when being moved from one chamber to the next. The transfer chambersare thus under vacuum and are “pumped down” under vacuum pressure. Inertgases may be present in the processing chambers or the transferchambers. In some embodiments, an inert gas is used as a purge gas toremove some or all of the reactants after forming the layer on thesurface of the substrate. According to one or more embodiments, a purgegas is injected at the exit of the deposition chamber to preventreactants from moving from the deposition chamber to the transferchamber and/or additional processing chamber. Thus, the flow of inertgas forms a curtain at the exit of the chamber.

During processing, the substrate can be heated or cooled. Such heatingor cooling can be accomplished by any suitable means including, but notlimited to, changing the temperature of the substrate support (e.g.,susceptor) and flowing heated or cooled gases to the substrate surface.In some embodiments, the substrate support includes a heater/coolerwhich can be controlled to change the substrate temperatureconductively. In one or more embodiments, the gases (either reactivegases or inert gases) being employed are heated or cooled to locallychange the substrate temperature. In some embodiments, a heater/cooleris positioned within the chamber adjacent the substrate surface toconvectively change the substrate temperature.

The substrate can also be stationary or rotated during processing. Arotating substrate can be rotated continuously or in discreet steps. Forexample, a substrate may be rotated throughout the entire process, orthe substrate can be rotated by a small amount between exposure todifferent reactive or purge gases. Rotating the substrate duringprocessing (either continuously or in steps) may help produce a moreuniform deposition or etch by minimizing the effect of, for example,local variability in gas flow geometries.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A method of depositing a metal film, the methodcomprising: exposing a substrate having a metal oxide first substratesurface and a dielectric second substrate surface to a first alcohol toreduce the metal oxide to a first metal and form an alkoxy-terminateddielectric surface; exposing the substrate to a first reactive gasconsisting essentially of a metal precursor comprising one or more ofcopper, cobalt, nickel or tungsten; and exposing the substrate to asecond reactive gas comprising a reducing agent consisting essentiallyof a second alcohol to deposit a metal film.
 2. The method of claim 1,wherein the substrate is exposed to the first reactive gas and thesecond reactive gas at the same time.
 3. The method of claim 1, whereinthe substrate is exposed to the first alcohol, the first reactive gasand the second reactive gas sequentially.
 4. The method of claim 3,wherein the substrate is moved laterally within a processing chamberfrom a first process region comprising the first reactive gas, through agas curtain, to a second process region comprising the second reactivegas.
 5. The method of claim 4, wherein during lateral movement of thesubstrate, portions of the substrate are exposed to the first reactivegas, the gas curtain and the second reactive gas at the same time. 6.The method of claim 1, wherein the substrate is exposed to the firstreactive gas and the second reactive gas at a temperature less thanabout 250° C.
 7. The method of claim 6, wherein the temperature is lessthan about 150° C.
 8. The method of claim 1, wherein the first alcoholand the second alcohol comprises one or more of a primary alcohol or asecondary alcohol.
 9. The method of claim 8, wherein the first alcoholand the second alcohol are independently selected from the groupconsisting of methanol, ethanol, 1-propanol, isopropanol, 1-butanol,1-pentanol, isopentanol, cyclopentanol, 1-hexanol, cyclohexanol,1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol,1-tetradecanol, 1-octadecanol, allyl alcohol (2-propen-1-ol), crotylalcohol (cis or trans), methylvinylmethanol, benzyl alcohol,α-phenylethanol, 1,2-ethanediol, 1,3-propanediol,2,2-dimethyl-1-propanol (neopentyl alcohol), 2-methyl-1-propanol,3-methyl-1-butanol, 1,2-propanediol (propylene glycol), 2-butanol,β-phenylethanol, diphenylmethanol, and combinations thereof.
 10. Themethod of claim 8, wherein the first alcohol and the second alcoholindependently have the general formula

where R and R′ are each independently selected from the group consistingof hydrogen, alkanes, alkenes, alkynes, cyclic alkanes, cyclic alkenes,cyclic alkynes and aromatics having in the range of 1 to 20 carbonatoms.
 11. The method of claim 1, wherein the first reactive gascomprises one or more of cyclopentadienylcobalt dicarbonyl (CpCoCO),dicobalt hexacarbonyl tert-butylacetylene (CCTBA),bis(2,2,6,6-tetramethyl-3,5-heptaneketoiminate)cobalt,bis(dimethylamino-2-propoxy)copper, bis(dimethylamino-2-ethoxy)copper,bis(1-ethylmethylamino-2-butoxy)copper,bis(1-ethylmethylamino-2-propoxy)copper,bis(dimethylamino-2-propoxy)nickel, orbis(2,2,6,6-tetramethyl-3,5-heptaneketoiminate)nickel.
 12. The method ofclaim 1, wherein the first alcohol and the second alcohol comprise thesame species.
 13. The method of claim 1, wherein the metal oxide of thefirst substrate surface comprises one or more of copper oxide, cobaltoxide, nickel oxide and ruthenium oxide.
 14. A method of depositing ametal film, the method comprising: providing a substrate having a firstsubstrate surface including a metal oxide and a second substrate surfaceincluding a dielectric; and sequentially exposing the substrate to afirst reactive gas consisting essentially of a metal precursorcomprising one or more of copper, cobalt, nickel or tungsten and asecond reactive gas comprising a reducing agent consisting essentiallyof an alcohol to form a metal film.
 15. The method of claim 14, whereinthe substrate is moved laterally within a processing chamber from afirst process region comprising the first reactive gas, through a gascurtain, to a second process region comprising the second reactive gas,so that during lateral movement of the substrate, portions of thesubstrate are exposed to the first reactive gas, the gas curtain and thesecond reactive gas at the same time.
 16. The method of claim 14,wherein the method occurs at a temperature less than or equal to about150° C.
 17. The method of claim 14, wherein the alcohol comprises one ormore of a primary alcohol or a secondary alcohol.
 18. The method ofclaim 14, wherein the alcohol is selected from the group consisting ofmethanol, ethanol, 1-propanol, isopropanol, 1-butanol, 1-pentanol,isopentanol, cyclopentanol, 1-hexanol, cyclohexanol, 1-heptanol,1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol,1-tetradecanol, 1-octadecanol, allyl alcohol (2-propen-1-ol), crotylalcohol (cis or trans), methylvinylmethanol, benzyl alcohol,α-phenylethanol, 1,2-ethanediol, 1,3-propanediol,2,2-dimethyl-1-propanol (neopentyl alcohol), 2-methyl-1-propanol,3-methyl-1-butanol, 1,2-propanediol (propylene glycol), 2-butanol,β-phenylethanol, diphenylmethanol, and combinations thereof.
 19. Themethod of claim 14, wherein the first reactive gas comprises one or moreof cyclopentadienylcobalt dicarbonyl (CpCoCO), dicobalt hexacarbonyltert-butylacetylene (CCTBA),bis(2,2,6,6-tetramethyl-3,5-heptaneketoiminate)cobalt,bis(dimethylamino-2-propoxy)copper, bis(dimethylamino-2-ethoxy)copper orbis(dimethylamino-2-propoxy)nickel, orbis(2,2,6,6-tetramethyl-3,5-heptaneketoiminate)nickel.
 20. A method ofdepositing a metal film, the method comprising: providing a substratehaving a metal oxide first substrate surface and a dielectric secondsubstrate surface; and exposing the substrate to a first alcohol in afirst process region of a processing chamber, the alcohol reducing themetal oxide to a first metal and forming an alkoxy-terminated dielectricsurface; laterally moving the substrate from the first process regionthrough a gas curtain to a second process region; exposing the substrateto a first reactive gas in the second process region, the first reactivegas consisting essentially of a metal precursor comprising one or moreof copper, cobalt, nickel or tungsten; laterally moving the substratefrom the second process region through a gas curtain to a third processregion; and exposing the substrate to a second reactive gas in the thirdprocess region to form a metal film, the second reactive gas comprisinga reducing agent consisting essentially of a second alcohol, wherein thefirst alcohol and the second alcohol are each independently selectedfrom the group consisting of methanol, ethanol, 1-propanol, isopropanol,1-butanol, isobutanol, 1-pentanol, isopentanol, cyclopentanol,1-hexanol, cyclohexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol,1-undecanol, 1-dodecanol, 1-tetradecanol, 1-octadecanol, allyl alcohol(2-propen-1-ol), crotyl alcohol (cis or trans), methylvinylmethanol,benzyl alcohol, α-phenylethanol, 1,2-ethanediol, 1,3-propanediol,2,2-dimethyl-1-propanol (neopentyl alcohol), 2-methyl-1-propanol,3-methyl-1-butanol, 1,2-propanediol (propylene glycol), 2-butanol,β-phenylethanol, diphenylmethanol and combinations thereof.